Lifejackets, or Personal Flotation Devices (PFDs) are a vital part of safety on any vessel. It's therefore important to understand what you're buying, or what you already own, when you should replace it and how to use it correctly. As a minimum there should be one of an appropriate type for every person on board. Boats venturing offshore should also carry spares.

What is a lifejacket?

At its simplest a lifejacket (often referred to as a Personal Flotation Device (PFD) by North Americans) is a device to help keep you afloat in the water. Early lifejackets were made of cork, but today's models are very different and use the latest technology for superior comfort and performance.

Keelboat lifejackets

The RNLI’s advice is that lifejackets are “useless unless worn.”

Lifejackets and buoyancy aids: what's the difference?

There is a crucial distinction between a device that’s intended as an aid to swimming (often used by dinghy sailors) and one with significantly more buoyancy that’s designed to flip an unconscious person face up and maintain that position, even in rough water. The former used to be referred to exclusively as buoyancy aids and typically have a 50 Newton rating. Somewhat confusingly, the EU standards don’t use the term buoyancy aid, so it describes all PFDs as lifejackets, even though only those with a 150N or greater rating will turn a casualty face up in the water.

In a nutshell, a product with a 50N rating is designed for watersports, where you expect to spend time in the water but when cold and tired may need help to swim. By contrast, a 150N (or greater) lifejacket is designed for those engaged in activities where there is never any intention of entering the water and may therefore be in a much more terrifying situation.

In cold water survival times for those wearing buoyancy aids can be as short as a few minutes – you rapidly lose consciousness and then are no longer able to your face clear to breathe. The difference with a 150N rated lifejacket is that you can continue to breathe when unconscious and deeply hypothermic, which can increase survival times to several hours. For leisure use buoyancy aids tend to rely on solid closed cell foam, whereas lifejackets are either manually or automatically inflated.

Lifejackets, or Personal Flotation Devices (PFDs) are a vital part of safety on board any floating vessel, so it's important to understand what you're buying, or what you already own, when you should replace it and how to use it correctly.

Buoyancy aids

All foam products with a 50N rating (known as buoyancy aids) are ideal for strong swimmers to wear when dinghy sailing, providing help is close at hand.

When should you wear a lifejacket?

A good lifejacket increases survival times from as little as a few minutes to several hours. In particular one with a 150N or greater rating will turn a casualty face up so they can continue breathing even if they fall unconscious through hypothermia.

There ought to be a single answer to when to wear personal buoyancy: all the time that you’re anywhere near the water. However, life is rarely so black and white. Most people, for instance, would agree that donning a lifejacket while enjoying a relaxed cup of coffee in the cockpit of a charter yacht on a still summer’s morning in the Mediterranean would be overkill. Nevertheless, it’s possible to identify plenty of situations in which failing to wear a lifejacket would be foolhardy. These include, but are by no means limited to:

  • While using the tender.

  • When under way at night.

  • In fog.

  • In strong winds.

  • For non-swimmers.

  • For children.

  • When directed to by the skipper.

  • In any situation in which you would feel more comfortable or confident.

  • In a distress situation, especially if you may have to abandon the boat.

In Britain there’s no legal requirement to wear a lifejacket while afloat on a vessel used solely for pleasure purposes. However, the RNLI recommends water users should: “Always wear an appropriate lifejacket or buoyancy aid unless it is safe not to do so… We believe that lifejackets save lives and are useless unless worn.” Find out more about the RNLI’s recommendations here:

It’s Important to remember that different rules apply in other jurisdictions. In Ireland, for instance, wearing personal buoyancy is mandatory for everyone on board any boat of less than 7m length, unless in an enclosed cabin below deck.

the gas on a lifejacket needs replacing regularly

The biggest single reason for a lifejacket failing to inflate is that the gas cylinder is not full screwed into place.

When to replace lifejackets

There has been a great deal of development in the design of lifejackets, over the past decade, with a focus on comfort and ergonomics, particularly at the higher end of the market. Therefore many 10-year-old designs now feel cumbersome to wear and restrict movement.

Improved design is not the only reason for buying new lifejackets – they also have a finite lifespan. The German manufacture Secumar, for instance, recommends inflatable lifejackets are serviced twice as frequently after 10 years’ use and are replaced after 14 years, even if on visual inspection the jacket appears to be in good condition. This applies irrespective of the amount of use – in many cases the first sign of aging is that the air bladder starts to become porous around any folds in the material. The recommendation is to replace foam filled 50N buoyancy aids at 10 year intervals.

Recent lifejacket developments

A sobering statistic is that the biggest single reason for a lifejacket failing to inflate is that the gas cylinder is not full screwed into place. Around 30 per cent of lifejackets inspected by the RNLI have this problem. Some of the more recent designs, such as Crewsaver’s ErgoFit series, address this issue with a pair of red and green flags that can be seen through a clear window in the outer cover. These indicate whether the inflation cylinder is properly screwed home, and whether the cylinder has been activated, making these items easy to check each time the lifejacket is used.

The lengths to which some of today’s lifejacket development are taken is illustrated by Spinlock’s latest models, developed in conjunction with Sir Ben Ainslie’s Landrover BAR America’s Cup team. As well as being carefully body contoured, these are wind tunnel tested to minimise windage when the boats are sailing upwind at speeds of close to 40 knots. In this market the benefits of such rigorous product development trickle down to more prosaic boaters surprisingly quickly.


A well fitting contoured model is ideal more likely to be worn than a less expensive cumbersome design.

How much flotation do lifejackets provide?

It’s important to distinguish between a proper lifejacket designed to turn a casualty onto their back, face up in the water, within five seconds and a buoyancy aid that’s intended as an aid to swimming. The latter is likely have only 50 Newtons of buoyancy – which is ideal for many watersports, but not for anyone on larger boats where contact with the water is not expected and recovering a person lost overboard would be fraught with difficulty.

Standard lifejackets have 150N of buoyancy, although 275N models are also available. The latter were mostly been developed for offshore industries – they have greater turning force because of the additional buoyancy, so will turn you into the upright position faster when wearing heavy protective clothing and may be helpful when sailing far offshore in extreme conditions. However, they are not necessarily a good solution for use on yachts and other small craft, as their considerable bulk when inflated can make recovering the casualty difficult. A common misconception is that these are intended for heavier people – this is not the case as most overweight people have a higher proportion of natural buoyancy than those of lighter build.

Lifejackets are also available with buoyancy levels of 165-190N. These provide a little more buoyancy than standard 150N models, with little extra bulk. It’s also worth noting that, somewhat confusingly, children’s inflatable lifejackets are labeled with the same buoyancy rating as the equivalent adult type, even though they provide less support. Find out more about buying lifejackets for children.

Types of lifejacket activation

There are three types of activation system for inflating lifejackets. The simplest and cheapest of these is manual activation – to fire the inflation mechanism the wearer must pull a toggle. This avoids the lifejacket accidentally inflating in rough weather, but also has a number of drawbacks. The biggest of these is the wearer must be conscious when hitting the water and must be able to find the toggle, which may not be easy in the first few seconds of panic. Even if the casualty was conscious when leaving the boat, cold water shock can immediately incapacitate an otherwise strong person, rendering them unable to activate the lifejacket.

Most automatic systems employ a bobbin between the gas cylinder and inflation chamber that swells when wet. It’s a simple arrangement that works well, providing the lifejacket is not left wet for long periods and the activator is replaced before the end of its expiry date – most last for two or three seasons. However, in extreme conditions they are at risk of accidental discharge, notably on the foredeck of large yachts powering through big waves at speed.

The Hammar hydrostatic system is designed to prevent these unwanted inflations – it’s operated by water pressure and will fire only after being immersed by more than 10cm for longer than two or three seconds. The downsides are that the cylinder is inside the inflation chamber, which makes servicing more difficult, there’s a small risk of creating an imperfect seal when changing cylinders and overall costs are greater.

Optimising lifejacket ergonomics

Choosing a lifejacket that’s uncomfortable to wear is usually a short-sighted decision as users are often be reluctant to wear it in borderline situations. Contoured soft collars are a great help in improving comfort levels, as a twin crotch straps or thigh straps. Models that are aimed primarily at the offshore yacht racing community tend to be by far the best in terms of comfort, ergonomics and freedom of movement. With a quality lifejacket you can also expect attention to be paid to minimising chafe that can lead to damage of the inflation chamber, especially around the metal gas canister.

Essential lifejacket extras

Few low specification lifejackets come fitted with lights or spray hoods and it’s only in the past few years that they have routinely been fitted with crotch or thigh straps. As a minimum, even if you intend to be afloat in sheltered waters during daylight hours only, each one should be fitted with marine grade retro-reflective tape and equipped with a whistle.

Crotch straps prevent a lifejacket riding up over the user’s head when they are in the water. The importance of this cannot be overstated – a lifejacket is useless if it’s floating above your head and there have sadly been a number of drownings at sea where exactly this has happened.

Lifejacket lights are usually activated by an automatic salt-water operated switch and can be an enormous help in locating a casualty at night. The lights are manufactured as a sealed unit, should be tested periodically and replaced before the expiry date marked on the case. Spinlock’s Lume-On system supplements conventional lights by making the entire lifejacket glow in the dark, making it much easier to judge distance from a casualty in the water on the final approach when attempting to manoeuvre alongside.

In anything other than fairly calm conditions, waves and spray will break over the head of a person in the water, even if they are properly supported by a lifejacket fitted with crotch or thigh straps. This of course makes breathing difficult at the best of times and all but impossible when suffering from cold shock or hypothermia. The solution is a spray hood - these significantly increase survival times by keeping spray away from your nose and mouth. It’s worth noting they are not deployed automatically, so it’s important to practice using them in advance.

Some lifejacket models also have provision for stowing electronic devices such as Personal Locator Beacons, AIS man overboard beacons, Search and Rescue Transponders or hand-held VHF units. These can be a huge help in both raising the alarm and in pinpointing the position of someone in the water.

A more recent development is the MOB Lifesaver that’s designed to help get an incapacitated person back on board. It’s essentially a strop, fitted to the lifejacket in advance, that can be reached by a crewmember on deck. It is currently type approved for use with models from Baltic, Sea Safe and Spinlock.

Safety harness and tethers

Lifejackets for sailing yachts should include a harness that enables the wearer to be clipped onto strong points on deck, and/or a jackstay that runs the length of the boat. Users of motor yachts don’t have the same need to work on deck while under way. However, it’s worth considering how you would secure a tow on the foredeck in a rising gale – this is one reason it’s frequently recommended that motor boats should carry at least two lifejackets on board that are equipped with harnesses.

The primary purpose of a harness is to minimise the risk of a person's torso becoming immersed in water outside the boat. Therefore, as well as the standard line of less than 2m length for every crew member, it’s also worth having some that are no longer than 1m long, or that have mid-point snaphook to allow for working on a short scope. The 2018 Offshore Special Regulations for racing yachts will require all crew to have three point tethers, with overload indicators, plus evidence of date of manufacture and compliance with ISO 12401. In addition, spare harnesses amounting to at least 10 per cent of crew numbers will be required to be carried on board.

Conventional wisdom has long suggested that the safety line has clips at both ends, to enable the line to be removed from your harness, for instance, if you are in the water and the boat is sinking. However Spinlock points out that it’s next to impossible to unclip a harness line when it’s under load, so the company supplies a safety knife that can be used to cut the line. A similar product is available for Crewsaver’s ErgoFit range.

Harnesses attachments are on the front of the lifejacket to make it easy to attach and remove the safety line. However, this means anyone falling overboard will be towed head first through the water. A new lifejacket/harness, developed by a young British sailor and engineer, Oscar Mead, addresses this problem. The harness line is attached to the front of the lifejacket in normal use, but if the wearer falls overboard the pull can be transferred to their back. The effect of this is that the casualty is towed along on their back, with their face lifted upwards and clear of the water. Read our report about the TeamO Back Tow lifejacket.

How many lifejackets are needed?

On the face of it this question has an easy answer – the maximum number of people you ever intend to sail with. However, there are situations in which it may be useful to have more than this. For instance, if a lifejacket inflates automatically in rough weather it’s much easier to don a spare than it is to deflate, re-arm and re-pack the original. For that reason, it’s worth carrying a couple of spares, as well as extra re-arming packs with gas cylinders and actuators.

Lifejacket care

Never stow lifejackets if they are wet and rinse any salt water off before drying. Lifejackets must be serviced at least once a year, including an inflation test. The inflation test can be done manually, ideally using a small hand pump, although more recent models can be orally inflated without causing longer term problems as a result of moisture. Jackets should retain air for at least 24 hours.

Gas cylinders and auto inflate actuating bobbins need to be replaced before their expiry dates, or if showing any evidence of damage. Lifejackets with hydrostatic inflation systems should be inflated after replacing the gas bottle and arming system, to confirm the seal between air cylinder and bladder remains effective.

As already indicated, the biggest single reason for a lifejacket failing to inflate in use is that the gas cylinder is not full screwed into place. Surveys have shown up to one-third of samples to have this fault, yet it takes only a few seconds to check each time the lifejacket is donned. At the same time it’s worth checking for any chafe damage to the outer cover or the webbing straps.

Lifejacket fitting

A sprayhood is essential to stop waves and spray making it impossible to breathe.

Lifejacket standards

ISO 12402 provides a uniform international standard for personal buoyancy, which supercedes the previous European standards. It details four performance levels, based on the level of buoyancy, measured in Newtons:

Performance level 275. For offshore use in extreme conditions when heavy protective clothing is worn or when extra loads are being carried. Turns unconscious wearers face up in water under almost all circumstances.

Performance level 150. For swimmers and non-swimmers of any age. Turns most unconscious wearers face up in water, depending on the clothing. May be suitable for use when foul weather clothing is worn and where wearers cannot help themselves.

There are also 150N lifejackets still available that aren’t inflated by a gas canister. These are the old-fashioned type with 100N of foam plus 50N of air that is added by orally. They are bulky and uncomfortable, so it’s not surprising they are rarely seen.

Performance level 100. Foam only product for use by good swimmers in relatively sheltered waters, will not turn unconscious wearers face up in water.

Performance level 50. Only for good adult (40+kg) swimmers for use in sheltered waters where help is close at hand. Will not hold the face of an unconscious wearer clear of the water. Not a lifejacket.

EN 1095 Safety Harnesses This standard is based on securing the wearer on deck, preventing them failing into the water and assisting the recovery of a casualty from the water. They aren’t intended to prevent vertical falls, such as when working up the rig.

Lifejackets are also available for pets… ‎and check out our top 10 tips for buying lifejackets for powerboats

Written by: Rupert Holmes
Rupert Holmes has more than 70,000 miles of offshore cruising and racing experience, in waters ranging from the North Sea to the Southern Ocean and Cape Horn. He writes about all aspects of boat ownership and marine travel, including destinations, seamanship and maintenance, as well as undertaking regular new boat and gear tests. He currently sails around 5,000 miles per year and in the past couple of seasons has cruised from the UK to the Azores, as well as winning his class in the 2014 two-handed Round Britain and Ireland Race. He also owns two yachts, one based in the Mediterranean and the other in the UK.